Preparation of rubber composition by aqueous elastomer emulsion mixing and articles thereof including tires

Abstract

This invention relates to preparation of a rubber composition by pre-mixing at least one rubber compounding ingredient with an aqueous emulsion, or latex, of at least one elastomer. The invention also contemplates the use of such rubber composition, or blend of such rubber composition with at least one additional elastomer and/or rubber compounding ingredient, as a component of an article of manufacture. Such article of manufacture may be, for example, a tire. Such article may also be an industrial product such as, for example, a hose or belt such as a conveyor belt or power transmission belt.

What is claimed is:  
     
       1. A process of preparing a rubber composition which comprises: 
       (A) blending a particulate elastomer-reinforcing filler and at least one additional rubber compounding ingredient with an aqueous emulsion of a conjugated diene-based elastomer and recovering a composition thereof by removing the water therefrom wherein said filler and compounding ingredient(s) are blended with said emulsion in a form of:  
       (1) particulate  
       (a) elastomer-reinforcing filler exclusive of aqueous or organic dispersion of said filler and  
       (b) at least one additional rubber compounding ingredient;  
       (2) particulate  
       (a) elastomer-reinforcing filler as a dispersion thereof in an organic solvent and  
       (b) at least one additional rubber compounding ingredient; and/or  
       (3) particulate  
       (a) elastomer-reinforcing filler as a dispersion thereof in water and  
       (b) at least one additional rubber compounding ingredient; or  
       (B) spraying an aqueous emulsion of a conjugated diene-based elastomer onto  
       (1) a particulate elastomer-reinforcing filler and  
       (2) at least one additional rubber compounding ingredient; and recovering a  
       composition thereof by removing the water therefrom;  
       wherein said reinforcing filler is selected from at least one of carbon black, synthetic amorphous precipitated silica aggregates and fumed silica, carbon black and modified carbon black having domains of silica on the surface thereof, and  
       wherein said additional rubber compounding ingredient is selected from at least one of  
       (A) additional diene-based elastomer(s) selected from homopolymers and copolymers of isoprene and/or 1,3-butadiene and copolymers of styrene with isoprene and/or 1,3-butadiene and their mixtures;  
       (B) sulfur;  
       (C) vulcanization accelerator(s) selected from dibenzothiazyl disulfide, 2-mercaptobenaothiazole, N-oxydiethylene benzothiazole-2-sulfenamide, 4-morpholinyl-2-benzothiazole disulfide, tetramethylthiuram disulfide, tetramethylthiuram monosulfide, tetrabutylthiuram disulfide, zinc dibutyldithiocarbamate, thiocarbqamuyl sulfenamide, N-cyclohexyl-2-benzothiazolesulfenamide, N-t-butyl-2-benzothiazole sulfenamide, and diphenylguanidine and their mixtures; and  
       (D) vulcanization retarders selected from N-nitrosodiphenylamine, N-cyclohexyl thiophthalimide, magnesium oxide, and N-(cyclohexylthio)-phthalimide and their mixtures.  
     
     
       2. The process of  claim 1  which comprises blending at least one particulate, elastomer reinforcing filler and at least one additional rubber compounding ingredient; or aqueous or organic solvent dispersion of said filler, with an aqueous emulsion of at least one diene-based elastomer to form a suspension, or dispersion, of said filler in said elastomer emulsion, followed by recovering said blend as an elastomer composite by removing water therefrom; 
       wherein said filler is selected from carbon black and silica and wherein said carbon black is exclusive of pelletized carbon black and wherein said silica is a fumed silica.  
     
     
       3. The process of  claim 1  wherein said blending.process comprises spraying said aqueous emulsion of at least one diene-based elastomer onto said particulate reinforcing filler and the at least one additional rubber compounding ingredient. 
     
     
       4. The process of  claim 1  wherein, for said spraying process, the aqueous emulsion of said elastomer(s) is substantially dried upon said particulate reinforcing filler and said at least one additional rubber compounding ingredient as it is being agitated. 
     
     
       5. The process of  claim 4  wherein, for said spraying process, said suspension, or dispersion, of said reinforcing filler, at least one additional rubber compounding ingredient and said aqueous emulsion of elastomer(s) is heat treated by heating the mixture, while agitating the mixture, to a temperature within a range of about 30° C. to about 150° C. for about 2 to about 30, minutes prior to drying the said composite. 
     
     
       6. The process of  claim 1  wherein said particulate reinforcing filler is comprised of at least one of carbon black, amorphous silica, and modified carbon black having silica domains on its surface. 
     
     
       7. The process of  claim 1  wherein an additional ingredient is blended with said elastomer emulsion, wherein said additional ingredient is selected from at least one of, based upon 100 parts by weight elastomer (phr): 
       (A) said sulfur vulcanization accelerator(s) in a range of about 0.1 to about 10 phr;  
       (B) said sulfur vulcanization retarder(s) in a range of about 0.01 to about 5 phr; and  
       (C) said sulfur in an amount of about 0.1 to about 3 phr.  
     
     
       8. The process of  claim 1  wherein said additional ingredient is said sulfur vulcanization accelerator. 
     
     
       9. The process of  claim 1  wherein said additional ingredient is said vulcanization retarder. 
     
     
       10. The process of  claim 1  wherein said additional ingredients are blended with said elastomer emulsion comprised of stearic acid and sulfur and also zinc oxide wherein said recovered rubber composite is sulfur vulcanized at a temperature in a range of about 150° C. to about 180° C. 
     
     
       11. The process of  claim 1  said filler is an amorphous silica which is pre-treated, prior blending with said aqueous emulsion of elastomer(s), by reacting said silica with an organosilane of the general formula (I) and/or II: 
       
         
           (OR) 3 —Si—R′—S n —R′—Si—(OR) 3   (I)  
         
       
       
         
           (OR) 3 —Si—R′—Z  (II)  
         
       
       wherein R is the same or different alkyl radical selected from at least one of ethyl and methyl radicals, preferably the same radicals and preferably an ethyl radical; R′ is the same or different radical selected from at least one of ethyl, propyl and butyl radicals, preferably the same radical and preferably a propyl radical; and n is a value from 2 to 6 with an average of from 2 to 2.6 or from 3.5 to 4 and Z is independently selected from —SH, —NH 2 , Acrylate, R′—NH—R′, epoxy, —SCN, —NCO, —Sn—NH—R′—Si—(OR) 3  groups. 
     
     
       12. The process of  claim 1  wherein said filler is a modified carbon black having domains of silica on the surface thereof, which is pre-treated, prior blending with said aqueous emulsion of elastomer(s), by reacting said modified carbon black having domains of silica on the surface thereof with an organosilane of the formula (I) and/or(II): 
       
         
           (OR) 3 —Si—R′—S n —R′—Si—(OR) 3   (I)  
         
       
       
         
           (OR) 3 —Si—R′—Z  (II)  
         
       
       wherein R is the same or different alkyl radical selected from at least one of ethyl and methyl radicals, preferably the same radicals and preferably an ethyl radical; R′ is the same or different radical selected from at least one of ethyl, propyl and butyl radicals, preferably the same radical and preferably a propyl radical; and n is a value from 2 to 6 with an average of from 2 to 2.6 or from 3.5 to 4 and Z is independently selected from —SH, —NH 2 , Acrylate, R′—NH—R′, epoxy, —SCN, —NCO, —Sn—NH—R′—Si—(OR) 3  groups. 
     
     
       13. The process of  claim 1  wherein said elastomer emulsion is a blend of at least two elastomer aqueous emulsions.